Symptom
- The interfaces on the Nexus will be suspended due to not receiving LACP PDUs
- On the IOS end, a log message is generated, such as:
"Apr 14 13:19:18.299: %EC-5-CANNOT_BUNDLE2: Gi6/46 is not compatible with Gi7/46 and will be suspended (Operational flow control send of Gi6/46 is off, Gi7/46 is on)"
Conditions
- An IOS device connected to a VPC Domain via port-channel
- One of the VPC switches in the domain is upgraded from 7.0(3)I7(6) or older to 7.0(3)I7(7) or newer.
- Flow Control is set to 'desired' on the IOS interfaces
Workaround
Disable flow control on the IOS interfaces so the inconsistency cannot exist
- "flowcontrol send off" under the interface configuration context
or
Upgrade the second VPC switch so the behavior is consistent
Further Problem Description
This is due to a change in behavior for NX-OS between 7.0(3)I7(6) and 7.0(3)I7(7) for LLFC.
